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(No Model.)

B. 0. PASOLDT. METALLIC PISTON PACKING.

No. 441,866. Patented Dec. Z, 1890.

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I lm b TEES cm, mom-mum, msumm'cn u c UNITED STATES PATENT QFFICE.

ERNEST G. FASOLDT, OF ALBANY, NElV YORK, ASSIGNOR OF ONE'IIALF TO JOHN BOYD THACHER, OF SAME PLACE.

METALLIC PISTON-PACKING.

SPECIFICATION forming part of Letters Patent No. 441,866, dated December 2, 1890.

Application filed September 17, 1889. Serial No. 824,188. (No model.)

To all whom it may concern: the attachment of said ring to the piston- Be it known that I, ERNEST C. FASOLDT, of head A.

the city and county of Albany, in the State E is the packing-ring, having a diameter of New York, have invented new and useful that fits the bore of the air-pump in which it Improvements in Metallic Packing for the is to be used. Said packing-ring has a coni- 55 Pistons of Air-Compressing Pumps, of which cal bore, so as to leave a very slight think the following is aspecification. ness-approximating a knife-edge-atifs up- This invention relates to metallic packing per end, and then gradually increasing in for pumps for compressing air, but especially thickness toward thelower end, at which point for the class of such pumps as are employed for a re-enforcing belt 4 is formed on the inner 6o compressing air to a high degree of density, side in order to obtain sufficient strength to wherein much difficulty is encountered in obcut a screw-thread therein, said screw-thread taining a piston-packing sufficiently tight to being fitted to screw onto the corresponding prevent a leakage that renders the obtainscrew-thread of the flange 2, so as to form a I5 ment of the required pressure a matter of close joint between the lower end of said 65 great and sometimes of insurmountable diffipacking-ring and the shoulder 5 of the pisculty. ton-head.

The object of my invention is to provide a F is a loose ring inserted between the bore metallic packing that will remedy the diffiof the packing-ring E and the outer face of culty above named, and I attain this object the ring D. The perimeter of said ring is 70 by the means illustrated in the accompanymade coniform to correspond to the bore of ing drawings,wl1ich are herein referred to, and the packing-ring E. Said ring is preferably form a part of this specification, in which supported on light springs 8 of sufficient Figure 1 is a vertical section of a piston strength to support the weight of said ring.

2 5 provided with the preferred form of my pack- The bore of said ring is provided at its upper 75 ing. Fig. 2 is a like section of a modified end with screw-threads 6, which correspond form of the same. Fig. is a plan view of to screw-threads 7, which are cut on the up- Fig.2, and Figs. 4 and 5 are enlarged and deper end of the perimeter of the cylindrical tached vertical sections of my packing-rings ring D. The lower portion of the bore of the illustrated in Fig. 1. ring F is of sufficient diameter to slip easily 80 As represented in the drawings, A desigover the screw-threads '7, and the lower pornates a piston-head, which may be of the tion of the perimeter of the body of the ring form shown in the drawings or in any other D is smooth and of such diameter that the form suitable for the purpose,'and B is the screw-threaded portion of the ring Fwill slip piston-rod, to which said piston-head is sefreely up and down thereon. The upper sur- 85 cured by any of the common and well-known face of the ringF receives the pressure of the means of eifecting such attachment. The compressedair and forces said ring downupper portion of said piston-head is reduced wardly into the annular space formed bein diameter to form the hub 1, upon the petween the rings 1) and E, and thereby effects 40 riphery of which ascrew-thread is cut for the the expansion of the packing-ring E, irreo purpose of receiving my packing. \Vheu spectively of the expansion produced by the preferred, the piston-head A maybe provided pressure of the compressed air acting against with spring'rings C of the form commonly the inner surface of saidring. employed for packing such pistons. In the packing shown in Fig. 2 the cylin- D is a cylindrical ring provided with a cirdrical ring D is made without the screw- 5 cumferential flange 2, having a screw-thread threads 7 (shown in Fig. 1,) and the ring F cut around its periphery. The bore of the (also shown in Fig. 1) is dispensed with, the ring D is provided with a screw-thread 3, pressure of the compressed air against the which is fitted to screw onto the correspondinner side of the ring E being relied upon to ing thread cut on the hub 1, so as to effect expand the packing-ring to closely fit the bore of the air-pump. This form of packing is found sufficient where a pressure 01": about a thousand pounds to the squareinch is only required. Vhen apressu re is required to exceed that figure,I prefer the form of packing shown in Fig. 1. \Vhen preferred, the rings D and and E can be made integral; but when they are made separately, as shown in the drawings, the ring E can be readily replaced without removing the ring 1). When the former has become worn by use and when preferred, the ring E can be spun up out of sheet metal, and in the latter case it should have" outer metallic ring that is used intact and V unslitt-ed, but is expansible by the pressure of the compressed air contained in the pump, said inner and outer rings being formed or connected together so as to form an annular groove between them, as and for the purpose herein specified. d

2. A metallic packing for pistons of aircompressing pumps; consisting of an inner metallic ring or head of cylindrical form and an outer metallic ring having a coniform bore and being expansible by the pressure of the compressed air contained in the pump, said inner and outer rings being formed or connected together so as to form an annular groove between them, and an intermediate ring having a coniform perimeter which'con forms to the bore of the outer packingring placed in said annular groove to effect the forcible'expansion of said outer ring, as and for the purpose herein specified.

ERNEST O. FASOLDT.

lVitnesses: VVIV'. H. Low,

S. B. BREWER. 

